As we enter a season of change, it's time to consider our sleep cycles

The arrival of spring represents the start of a new lifestyle for many people, especially in Japan. It's a time of change. However, at the same time, people may need to think about their personal sleep cycles as they enter the new season.

In particular, the people who need to be careful are those who are used to staying up late or working night shifts, and who have to adjust to a more morning-oriented lifestyle due to a new job or an internal work transfer.

The Mainichi Shimbun interviewed Kazuo Mishima, a senior researcher at the National Institute of Mental Health, National Center of Neurology and Psychiatry and an expert in sleep treatment about how one should go about normalizing one's sleep cycle when changing lifestyles.

Mishima explained that humans possess body clocks that beat out rhythms over one-day cycles. If the body clock is functioning normally then one's body and brain work well throughout the day and naturally switch to a relaxed state at night before bedtime. If the clock becomes disrupted, it will worsen the sleep cycle, making it difficult to drift off at night and wake up in the morning.

People who are still working and who have drastically changed their lifestyle after undergoing major changes in environment should re-examine the way they sleep. People's body clock tends to slow down in their 20s and 30s even if they went to bed early and woke up early in childhood.

However, Mishima points out, "If you neglect your body clock, you will end up becoming a night person. It's necessary to rewind the clock by exposing yourself to the early morning sun."

Youngsters switching from university lifestyles to conventional working days also need to take heed. What happens when they need to switch from staying up late, to going to work at a fixed time in the morning, and having to perform well throughout the day?

It's an issue, because many youngsters in this position are diagnosed with "irregular sleep-wake rhythm disorder" at the start of spring. Problems include not being able to fall asleep and wake up at a fixed time, or drowsiness, headaches, fatigue or loss of appetite during the day. In the worst cases, some people reportedly end up quitting their jobs or taking time off work.

"It takes about three weeks to improve one's sleep patterns," Mishima explains. To start with, one should try to expose oneself to the morning sun for about 30 minutes to one hour, and not keep looking down at the ground. So let's open the curtains as soon as we wake up, and look straight ahead beyond the window -- as it's important for our retinas to feel natural light.

Exposure to artificial light at night just slows down the body clock. Devices such as LEDs, smartphones and computers emit something called blue light, which should ideally be avoided at night time.

Something else to be careful of is the practice of "saving sleep hours" on the weekend. "Saving sleep hours on the weekend leads to fatigue during the week, and even a depressive state," Mishima warns. Waking up late on a Saturday or a Sunday messes up the body clock and creates a jet-lag like condition known as "social jet lag."

When this happens, it takes three weeks to return the body clock to a normal state. For those who argue that "saving sleep hours" is necessary to avoid drowsiness on the weekend, wake up early at a "weekday waking time," and beat it by having a nap of about 20 to 30 minutes in the daytime.

Also, those who go by the "sleep anytime, anywhere" motto are also at risk. "People who have enough sleep need about 10 to 15 minutes to get to sleep," Mishima says. In other words, people who snatch some shuteye whenever and wherever they can are experiencing chronic sleep problems. Some people who have sleep apnea syndrome reportedly say things like, "I don't feel drowsy," even at times when they are low on sleep.

"You mustn't judge (your sleep needs) according to how drowsy you feel. People who think they can get through the day by drinking coffee and energy drinks are especially at risk. Their bodies are raising alarm bells that (the sleep cycle needs to be improved)," Mishima says. "An irregular sleep pattern can increase the risk of all kinds of illnesses such as heart disease, diabetes, and psychiatric disorders. Before that happens, please re-examine the way you sleep as soon as possible." (By Satoko Nakagawa, Lifestyle News Department)